Abstract I am a clinical psychiatrist by training, and neuroscientist. I have devoted my research career to understanding mechanisms, nature and time-course of intractable psychiatric illnesses, such as obsessive compulsive disorder (OCD). I am an Associate Professor in the Departments of Psychiatry and Neurology at Massachusetts General Hospital (MGH), Harvard Medical School. I serve as Director of the Center for Morphometric Analysis, Department of Psychiatry at MGH, and as Director of Computational Imaging Anatomy at the Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Brigham & Women?s Hospital (BWH), where I hold secondary appointments, at Psychiatry and Radiology, as a research scientist. I have been conducting NIH sponsored research since 2003, when I received my first R03 award. I am currently a PI on two NIH grants (R01, funded by NIA & NIMH; R21 funded by NCCIH) focused on understanding mechanisms of brain development, maturation and aging through a set of neuroimaging tools and their validation in rhesus monkeys. Those two grants together have the potential of delivering validated neuroimaging biomarkers, which could be used to diagnose and monitor neurobiological changes due to myelin loss and neuroinflammation in aging, and a whole list of other neuropsychiatric diseases where those changes are involved. Furthermore, I?m a PI in a new grant (R01MH111917), which specifically focuses on retrospective investigation of imaging- based targeting for DBS in OCD and serves as the scientific basis upon which this K24 application is hoping to extend in depth and scope. Besides my research, I am also involved in mentoring Harvard, MIT and BU undergraduate and graduate students, postdoctoral fellows (including K23 awardees), foreign fellows, and summer students. I am also involved in administrative work, as head of two large laboratories, at MGH and at BWH, and various local and regional committees. Finally, I am getting involved in nonclinical and non-POR research (through my ongoing and pending animal projects), and that takes away from both my mentoring and my POR research. The K24 would protect time and help me to focus on most important for my career development- mentoring (30%), further training and new POR (20%), while devoting remaining 50% to ongoing neuroimaging research in biomarkers of white matter changes in aging and OCD.